Pfizer’s Biosimilar Zirabev Approved in E.U. for Advanced Breast, Other Cancers

Metastatic breast cancer patients in the European Union will have the possibility of being treated with a biosimilar of Avastin (bevacizumab), following the approval of Pfizer’s Zirabev (bevacizumab) as a more affordable treatment with similar efficacy to the original.

Zirabev is the second biosimilar to Avastin approved by the European Commission and covers its use in five indications in the original treatment’s label, including in combination with the chemotherapy Taxol (paclitaxel) for the first-line treatment of breast cancer patients with metastatic disease.

Biosimilars are biological medical products that are nearly identical to an original product, but manufactured by a different company after the original product’s patent expires. They usually are sold at significantly lower prices.

Unlike chemical compounds, which are made through chemical reactions, biological medicines are grown in cells and may show some differences from similarly designed products.

As a result, regulatory agencies require extensive data showing that a biosimilar has equivalent safety and effectiveness, and behaves similarly in the body in regard to absorption, distribution, metabolism, and excretion, to the original medicine.

Avastin is an antibody that targets the VEGF molecule, which helps cancers grow blood vessels so they receive enough nutrients and oxygen to survive and thrive. It is approved for 10 indications, including colon, breast, lung, kidney, ovarian, and cervical cancers. But its patent will expire in the U.S. in July 2019 and in Europe in January 2022, and cheaper options are now emerging.

The European Commission’s decision, which follows a positive recommendation from the agency’s Committee for Medicinal Products for Human Use, was based on data showing the structural and functional similarities between Zirabev and Avastin, in addition to preclinical and clinical trial data showing similar safety and effectiveness.

In a Phase 3 trial, called REFLECTIONS B739-03 (NCT02364999), Pfizer compared its proposed biosimilar to the original product, when used in combination with chemotherapy for first-line treatment of advanced non-squamous non-small cell lung cancer.

A total of 719 patients, median age 61 years, were randomized to either Zirabev or Avastin, along with chemotherapy — Paraplatin (carboplatin) plus Taxol — for up to six cycles. Patients were then treated with Zirabev or Avastin as maintenance therapy until their disease progressed or signs of unacceptable toxicity were reported.

Researchers found that a similar proportion of patients responded to both treatments — 45.3% for Zirabev and 44.6% for Avastin. The number of patients living past the one-year mark without disease worsening was also similar for both medicines — 29.4% and 29.3% — as was the survival rate at one year (65.2% and 66.4%).

The rate of adverse events was also similar between the groups.

“Pfizer is dedicated to increasing access to biosimilars for patients suffering from serious illnesses and helping create a more sustainable healthcare system,” Andreas Penk, MD, regional president, Oncology International Developed Markets at Pfizer, said in a press release.

In addition to the metastatic breast cancer indication, Zirabev is also approved for metastatic colon or rectal cancers, advanced non-small cell lung cancer, advanced renal cell cancer, and hard-to-treat advanced cervical carcinoma. A similar application has been filed with the U.S. Food and Drug Administration.

“We are proud that Zirabev was approved … as our second oncology biosimilar in Europe. This milestone reflects our ongoing commitment to biosimilars as we continue to bring high-quality medicines to market that may help generate cost savings for cancer care,” Penk said.